This invention relates generally to steering column slider assemblies and more particularly to steering column slider assemblies with combined sealing and anti pull-apart features.
Steering columns in motor vehicles include slider assemblies, made up of a shaft and yoke, or shaft and foot, assembly slidably inserted within a tube and yoke, or tube and foot assembly, to accommodate variations in the distance between the vehicle dash panel and the steering gear box due to manufacturing tolerances. Use of the slider shafts facilitates assembly of the vehicle by accommodating slight variances in the positions of the steering gear box and the steering column. Slider shafts are also required for providing reach, or length, adjustability in steering columns.
Normal driving conditions also entail road shocks which cause relative motion between the body and frame. These move the steering gear box and the steering shaft connected to it. The slider shaft permits telescopic compliance of the steering shaft and absorbs the road shocks with minimal effect on the upper portion of the steering column and, thus, comfort of the operator. The normal telescopic motion of the slider is in the range of xc2xdxe2x80x3 or less.
Vehicle designs have become smaller and often require the steering column to have one or more bends to reach the steering gear box. Each such bend requires at least one universal joint which requires a significant axial space. As a result, slider shafts have become quite short in some designs in which the distance between the dash panel and the steering gear box is small and the angular deviation is relatively large.
Because of their location in the vehicle, the slider shafts are exposed to water, salt, and road debris which cause corrosion and wear and which ultimately lead to deterioration of the slide function and an objectionable degree of rotational lash in the steering mechanism. Rubber sealing boots are installed on the shafts and tubes of many slider assemblies to retain lubricant and exclude contamination, but they do not seal the ends of the shaft and the tube. Also, they eventually crack, due to mechanical, thermal, or chemical attack, or otherwise develop leaks which permit loss of lubricant and entry of the contamination at the slider joint.
Currently, in order to prevent inadvertent separation of the tubes and shafts of slider assemblies during subsequent assembly into the steering column of the vehicle, the end of the shaft is deformed, by staking or otherwise, after insertion into the tube. This is a very effective retention measure, and, except when the slider becomes too short, suffices. However, at or near some lower limit of slider length, there is insufficient space to permit such deformation of the end of the shaft after assembly, and another method must be found to provide the anti-pull-apart feature.
The foregoing illustrates limitations known to exist in present sealing and anti pull-apart features of steering shaft slider assemblies. Thus, it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.
In one aspect of the present invention, this is accomplished by providing a steering column slider shaft assembly which comprises a shaft assembly with a yoke at a first end thereof and an attached non-cylindrical shaft extending therefrom to a second end; a tube assembly comprising a non-cylindrical tube with an attached yoke at a first end, the tube being congruent with and adapted to slidably receive the shaft and to provide a slip fit therefor within a second end thereof; and means for sealing the slider shaft assembly.
The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.